granicus.if.org Git - strace/blob - readlink.c

   1 /*
   2  * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
   3  * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
   4  * Copyright (c) 1993-1996 Rick Sladkey <jrs@world.std.com>
   5  * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
   6  * Copyright (c) 2006 Ulrich Drepper <drepper@redhat.com>
   7  * Copyright (c) 2006 Bernhard Kaindl <bk@suse.de>
   8  * Copyright (c) 2006-2015 Dmitry V. Levin <ldv@altlinux.org>
   9  * Copyright (c) 2014-2019 The strace developers.
  10  * All rights reserved.
  11  *
  12  * SPDX-License-Identifier: LGPL-2.1-or-later
  13  */
  14
  15 #include "defs.h"
  16
  17 static int
  18 decode_readlink(struct tcb *tcp, int offset)
  19 {
  20         if (entering(tcp)) {
  21                 printpath(tcp, tcp->u_arg[offset]);
  22                 tprints(", ");
  23         } else {
  24                 if (syserror(tcp))
  25                         printaddr(tcp->u_arg[offset + 1]);
  26                 else
  27                         /* Used to use printpathn(), but readlink
  28                          * neither includes NUL in the returned count,
  29                          * nor actually writes it into memory.
  30                          * printpathn() would decide on printing
  31                          * "..." continuation based on garbage
  32                          * past return buffer's end.
  33                          */
  34                         printstrn(tcp, tcp->u_arg[offset + 1], tcp->u_rval);
  35                 tprintf(", %" PRI_klu, tcp->u_arg[offset + 2]);
  36         }
  37         return 0;
  38 }
  39
  40 SYS_FUNC(readlink)
  41 {
  42         return decode_readlink(tcp, 0);
  43 }
  44
  45 SYS_FUNC(readlinkat)
  46 {
  47         if (entering(tcp)) {
  48                 print_dirfd(tcp, tcp->u_arg[0]);
  49                 tprints(", ");
  50         }
  51         return decode_readlink(tcp, 1);
  52 }